from typing import List

n,k = map(int,input().split(' '))

c=" "+input()
num:List[List[int]] = [[0]*(n+1) for _ in range(n+1)]
dp:List[List[int]] = [[0]*(n+1) for _ in range(n+1)]

for i in range(1,n+1):
    num[i][i] = int(c[i])
    # print(num[i][i])
    for j in range(i+1,n+1):
        num[i][j] = num[i][j-1]*10 + int(c[j])
        # print(num[i][j])
    dp[i][0] = num[1][i]

for j in range(1,k+1):
    for i in range(j+1,n+1):
        for fk in range(j-1,i):
            # print(i, j, dp[i][j], dp[k][j-1]*num[fk+1][i])
            dp[i][j] = max(dp[i][j], dp[fk][j-1]*num[fk+1][i])

print(dp[n][k])